A new method of recording both video and audio data upon a recording medium, (e.g. formed on a recording disc whose contents are read out by an optoelectric type of pick-up) has been disclosed in Japanese application Pat. No. 58-45780 (provisional publication number 59-171011). The subject matter is also disclosed in U.S. patent application Ser. No. 527,721 filed Aug. 30, 1983. With this method, an audio signal is converted into a digital signal in PCM (pulse code modulation) ) form, and this PCM digital signal is superimposed upon frequency modulated audio and video components, which modulate a RF (radio frequency) carrier. The three types of data are recorded in the form of a pulse-width modulated signal, whose frequency spectrum includes the essential frequency components of the digitally modulated audio signal and the frequency modulated audio and video signals. Such a recording system has the advantage that the quality of reproduced sound which can be obtained from digital modulation is substantially higher than is obtainable with recording using frequency modulation, so that by providing a suitable PCM encoder within a video recording disc player it becomes possible to play such discs and thereby obtain the improved sound quality of digital recording.
However incorporation of a PCM encoder circuit and associated circuits (e.g. for clock signal generation etc) within a video recording disc player will substantially increase the manufacturing cost of such a player, and there is therefore a requirement for means whereby such a new type of video recording disc having audio data digitally recorded thereon can be played on a video recording disc player without the necessity of utilizing a built-in PCM encoder.